Bag structure with integral closure arrangement

ABSTRACT

To provide a closure for bags of flexible material such as polyethylene, light fabric, or the like, a restricted opening is formed near the top of the bag, for example by a seam partitioning off a portion of the mouth of the bag, a pair of seams extending towards a side with the side being slit open between the seams, or a pair of seams between which a slit is cut; the size of the opening is just large enough to enable a user to gather together the remainder of the mouth of the bag and push it through the opening, the released gathered material then flaring out by its own elasticity to provide a closure which will securely hold contents within the bag.

United States Patent Lake [541 BAG STRUCTURE wmr INTEGRAL CLOSURE ARRANGEMENT [72] inventor; Connie Lake, Pittsi'ord, N.Y. [73] Assignee: Mobil Oil Corporation [22] Filed: Dec. 12, 1969 [21] Appl. No.: 884,534

[52] U.S.C1 ..229/62, l50/3,53/40 1 [58] Field 01 Search ..229/53, 62; 150/3; 53/40 [56] References Cited UNITED STATES PATENTS 1,236,285 8/1917 Gallie ..150/3 3,217,934 11/1965 Schneider ..229/63X [451 Apr. 4, 1972 FOREIGN PATENTS 0R APPLICATIONS 1,088,414 10/ 1967 Great Britain ..229/62 Primary Examiner-Donald F. Norton Attorney-Oswald G. Hayes and Andrew L. Gaboriault [57] ABSTRACT To provide a closure for bags of flexible material such as polyethylene, light fabric, or the like, a restricted opening is formed near the top of the bag, for example by a seam partitioning off a portion of the mouth of the bag, a pair of seams extending towards a side with the side being slit open between the seams, or a pair of seams between which a slit is cut; the

size of the opening is just large enough to enable a user to gather together the remainder of the mouth of the bag and push it through the opening, the released gathered material then flaring out by its own elasticity to provide a closure which will securely hold contents within the bag.

18 claim, 12 Drawing Figures Patented April 4, 1972 3,653,584

3 Sheets-Sheet 1 Patented April 4, 1972 3,653,584

25 Sheets-Sheet 2 BAGSTRUCTURE WITH INTEGRAL CLOSURE ARRANGEMENT FIELD OF THE INVENTION The present invention relates to bag structures, and more particularly to bag structures intended to be made of a flexible material, such as polyethylene, fabric, or the like, and which is constructed to provide an arrangement so that the bag can be closed, without requiring any external auxiliary closing elements, or ties.

BACKGROUND OF THE INVENTION Polyethylene bags, as used for sandwiches, liners for wastepaperbaskets, trash cans, garbage pails, leaf bags, and for other many uses requiring manual closing by the user without special apparatus, such as heat sealing devices, should preferably be so constructed that they can be closed without additional elements or ties. To close polyethylene or similar bags, paper covered wires known as twisters are frequently used; while such separate elements as twisters, string, or other wire closures effectively'elose any flexible bag, they have two distinct disadvantages: they are a separable element, frequently not handy when a bag is ready to be closed and,-additionally, they are expensive to supply and require an additional packaging step in the sale of bags.

Closures for bags should have a number of characteristics to make them fully acceptable for everyday use. They should be simple to operate, that is quickly applied, since the closing operation is one which is frequently done repetitively, and therefore should be fast, without requiring manual dexterity. The cost of the closure should be low preferably so low that the cost of the entire bag is not noticeably increased thereby. In this particular aspect, the twister is undesirable, since it is not only a separate item requiring separate handling in packaging, but for small bags, may approach in cost the cost of the bag itself. The closure should further be adjustable to the size of the load, or contents to be placed into the, bag, so that the load does not move around within the .bag excessively, or leave the-bag only half filled if less than full capacity is placed thereinto. The twister-type closure serves admirably in this respect. The closure should further be integral with the bag, so that it cannot be lost, misplaced, or has to be looked for when it is desired to close the bag. This is one of the principal disadvantages of the separate twister wire. The closure must further be efficient, that is it must be tight enough to prevent spillage of the contents and additionally prevent exchange of air from within the bag to the outside, penetration of rain, moisture or the like, or escape of odors and fluids from the bag. The closure must also be compatible with other closures generally available on the market, that is it must be so constructed that no special technique need be learned to close the bag. It should be adaptable to customary human manipulation, and require only one hand for its use, leaving the other free to support the bag. The twister is particularly deficient in this respect since two hands are needed to tie a twisting wire properly, which introduces difficulty in holding the mouth of the bag gathered together for application of the twisting wire. A desired feature in the closure is the capability to be used repetitively, that is to enable the bag, with the closure to be reused, and the bag re-closed with the same element. Further, the closure should have handling capability, that is it should be so arranged that a full bag can be picked up by the closed mouth, without fear of tearing or placing undue strain at specific points of the bag. This requires the additional characteristic of adequate closure strength that is, the closure should be strong enough to permit inversion of the bag without escape of any of the load therein, within the rated weight holding capacity of the bag. While it is not always necessary to provide a closure strong enough to permit a fully loaded bag to be turned upside down, it is a highly desirable feature, particularly for bags used in the trash disposal field.

It is, therefore, an object of the present invention to provide a closure arrangement which can be constructed to be integral with a bag to which it is applied, is simpleand cheap in construction and adds little or no cost to the bag while exhibiting the desirable characteristics of an effective closure.

SUMMARY OF THE INVENTION Briefly, the bag structure is arranged to have, near the mouth thereof, a passageway, in the form ofa restricted opening of such size that the entire material of the walls of the bag, in the region of the mouth, can be gathered and drawn tightly together and then inserted from the inside of the bag through the passageway; after release of the gathered material, that portion thereof which extends beyond the restricted opening formed by the passageway will flare out due to its own, natural elasticity, providing a tight effective closure for the bag.

In one embodiment of the present invention,'the closure is defined by forming a seam near the top of the bag, preferably offset below the rim'of the mouth by a distance sufficient to permit overlapping of the rim about the edge of a pail; the seal may extend vertically, closing off a'minor portion of the width of the bag and defining the opening between the seam and the walls.'This construction, when applied to polyethylene bags, adds practically no cost to the bag at all, since no additional material is necessary in its manufacture and the additional manufacturing step of providing the seam can be carried out during manufacture of the bags, automatically, with low-cost machinery attached to existing plastic bag machines. In another form of the invention, a plurality of layers of the bag are folded together, seamed (again, for example, by plastic heat welding) together to form a reinforced section, with a slit placed between the seams to form the restricted opening. The slit, again, is preferably located below the rim of the bag. This is a particularly desirable construction when resistance to exchange of air, or moisture between the inside of the bag and ambient surroundings is desired. In another form of the invention, a pair of scam lines are formed to extend essentially parallel with the mouth of the bag, towards a lateral edge of the bag, which is then slit between the seams, the region between the seams with the slit edge defining the restricted opening. This, also, is a constructionwhich has a high degree of isolation of the contents of the bag with ambient air.

In accordance with another embodiment of the present invention, a strap is applied near the mouth of thebag to define, together with the underlying portion of the wall of the bag, a restricted opening through which the remainder of the material forming the mouth of the bag can be drawn. By making the strap of a material contrasting, or different from that of the bag itself, for exampleof contrasting color, with a different surface texture, or even slightly tacky, decorative effects can be obtained and, additionally, the holding efficiency of the closure improved.

BRIEF DESCRIPTION OF THE DRAWINGS Advantages of the invention will become apparent to those skilled in the art from the following description considered in conjunction with the drawings wherein:

FIG. la is a pictorial, schematic representation of the bag structure, with the opening arrangement;

FIGS. 1b and 10 show, progressively, the steps in closing the bag by using the structure in accordance with the present invention;

FIG. 1d illustrates, in schematic form, the bag when closed;

FIG. 2 is a view of the region within the dashed lines of FIG. 1a, to greatly enlarged scale, and showing various modifications;

FIG. 3 is a fragmentary view of another modification of the invention;

FIG. 4 illustrates, in a fragmentary view, a different embodiment;

FIGS. 5a and 5b illustrate another embodiment of the invention, applied to an edge-folded bag (FIG. 5a) or a gussetted bag (FIG. 5b), respectively;

FIG. 6 illustrates the invention as shown in FIG. 2 and applied to a gussetted bag;

FIG. 7 shows another embodiment of the invention, in a fragmentary view; and

FIG. 8 shows an arrangement of the closure with a draw tape.

The general form of the bag construction, best seen in FIG. la, is standard. A front wall 10 and rear wall 11, for example formed as an integral, unitary tube define a mouth 12. The bottom edge 14 of the bag can be sealed off by a seam 13.

A seam 15, parallel to the lateral edges of the bag, together with the lateral edges defines a restricted opening 16. The area within the dotted circle is illustrated at an enlarged scale in the subsequent figures, where also different embodiments of the basic bag structure will be explained.

To close the bag, the area within the dash-dotted oval in FIG. 1b is gathered together, as illustrated in the initial gathering stages at 17 in FIG. 10, for example by one hand, the other hand holding the bag in the region of the seam 15 and the restricted opening 16. The gathered material is then inserted, following the arrow A by threading underneath the seam line 15 into the opening 16 and drawing the gathered material out of the opening 16, as illustrated by the terminal end B of the arrow. A filled bag is illustrated in FIG. 1d. The gathered material of the mouth region of the walls 10, 11 will flare out, as at 18. It can readily be seen that the bag can be drawn through the opening to the extent necessary as determined by the contents C to be placed in the bag. Thus, for a smaller number, or lesser quantity of contents, the mouth section of the bag walls need only be drawn out higher. The bag itself is preferably made of polyethylene, which may be opaque in any color, transparent, or translucent. The polyethylene may be smooth, embossed, or have any desired surface texture. A slightly rough surface texture improves the adhesion of the polyethylene material to the wall section of the openings and further improves the holding strength of the closure structure.

FIG. 2 illustrates the closure structure just described in greater detail. For a bag which may be typical for a trash basket liner of flat dimensions of overall length of about one meter, with a width of 90 cm, a seam of length L of about 5 cm is suitable. The offset 0 from the top edge of the walls, that is the downward dimension from the mouth opening can be in the order of 12 cm. The distance from the edge of the bag, that is the diameter D of the opening, when laid out flat, is in the order of 5 cm. None of these dimensions are critical and are given herein only as an example; the dimensions themselves may be varied depending upon the material, its texture, the thickness thereof, and many other considerations, for example the intended use. When a bag in accordance with the present invention is installed in a trash barrel, and the like, to be used as a liner, it is desirable to offset the seam l5 downwardly from the edge of the mouth. Shown schematically is a wall W of a trash container. The plastic bag is inserted as a liner, and the top edge folded downwardly as schematically indicated by the chain-dotted arrow 20, so that the top edge of the material will assume the position shown in dashed lines 21. Offsetting the seam 15 as illustrated in FIG. 2 permits folding over of the liner; it does, however, somewhat decrease the capacity of the bag. For small bags, which are not to be used as liners, such as sandwich bags, or the like, the seam 15 can be placed, as seen in FIG. 3, up against the top edge 25 of the walls. This increases the capacity of the bag without requiring an increased amount of bag material.

The seam 15 is preferably formed by heat sealing the opposed walls 10, 11 together. Such heat sealing is well known in the art, and can be carried out at a seaming station, as an attachment, applied to any existing plastic bag manufacturing machine.

FIG. 4 illustrates a different form of the present invention, in which the restricted opening is formed in the side walls. Front wall 10, and rear wall 11 of the bag are again seamed together by a pair of seams 45, 45, extending essentially parallel to the top edge 25 of the walls. The seam 45 is-again offset from the top by a distance 0. Since the material between the seam 45 and the top edge will also be available to be folded inwardly through the opening 46 defined between the two seam lines 45, 45 this type of construction provides a very effective seal against interchange of air, or moisture, or liquids from within the bag to surrounding ambient air, and thus effectively prevents entrance of rain, or other moisture to within the bag. The closure construction in accordance with FIG. 4 can, on an existing bag machine, again be made by forming the two seams 45, 45' by a heat sealing device. The bag is then cut off at the edge, set in by a very small amount I which is shown in the drawings greatly exaggerated. Cutting off a thin sliver of material is an effective and inexpensive way of forming the opening. The distance I, itself, can be determined by manufacturing tolerances and may be 0.1 mm, or even less.

An opening with reinforced strength is illustrated in FIG. 5a. Terminal portion of the bag is wrapped about itself a few times as seen at 51 to form a plurality of layers, in the case illustrated in FIG. 4 as six layers. Such folding operations can readily be carried out on existing bag manufacturing machinery. The folded-over edges are then heat seamed together in a pattern illustrated as a double cross pattern 52, although any other suitable pattern may be used. A slit 56 is then cut between the seam line; the width of the slit is shown exaggerated in the drawings. To increase the strength of the slit, it can be terminated either at one of the seam lines, or have terminal loops 57, 57 formed by heat sealing. The loops 57, 57' are preferably applied by heat sealing, and extend through the various layers of material, to the rear wall 11. The number of folds 51 will affect the strength of the opening; this type of bag closure also has a high degree of moisture and fluid penetration resistance since the portion of the folded-over material which is seamed together at seam pattern 52 will provide a water-tight region, and the remainder of the top of the bag can be gathered together and packed into the slit 56, to be drawn therethrough in the direction back of the drawing, FIG. 5a, to provide a complete closure-and seal. A structure similar to that shown in FIG. 5a with a gussetted bag is illustrated in FIG. 5b. The gussets, folded in a gussetting machine, are seamed together at the pattern 53, slit 56 again being formed between seam lines. If a seam line as illustrated in FIGS. 2 and 3 is to be used with a gussetted bag, then the seam preferably extends only from the front wall to a folded portion, within the gusset, as illustrated in FIG. 6. Front and back walls 10, 11, are interconnected by a gusset fold 60, 61. Seam 65 interconnects gusset fold 60 and front wall 10, the opening 66 being defined by the region between seam 65, front wall 10, and first gusset fold 60.

FIG. 7 illustrates a construction in which the strap 71 is heat seamed at 75, 75' to extend across a portion of the rear wall 1 1 of the bag structure, of which only the top part is shown in a fragmentary view. The region between strap 71 and back wall 11 defines the opening 76 of restricted size, through which the top portion of the bag material can be drawn, when walls 10, 11, are gathered together tightly, to be drawn through opening 76 between strap 71 and wall 11. Strap 71 may be made of a material of color contrasting with the color of wall 11, so as to,be easy to find; the material can be different from that of the walls; its surface texture, particularly on the inside face, that is the face adjacent rear wall 1 1 may be roughened to increase adhesion with the gathered end portions of the walls when drawn through. Further, the inside can be made slightly tacky to securely hold any material drawn therethrough.

Various modifications and changes of the formation of the restricted opening are possible, and will be dictated by the use for which the bags are intended, their size, the material used, and the like. For example, it is not necessary that the seam line 15 (FIG. 2, FIG. 3) or the slit 56 (FIG. 5) is parallel to the side edge of the bag. The seam 1 5 may well be arranged on a slant, for example parallel to the dashed line 19 (FIG. 2), so that the smallest opening formed has a dimension less than dimension D, to compress the gathered-together folds of the material and provide a tighter seal, without, however, restricting the widest portion of the opening 16 and thus interfering with the ease of insertion of the gathered material. Likewise, the seams 45, 45' (FIG. 4) may be arranged to converge towards opening 46, thereby also providing for ease of insertion-with a tight fit of the bunched-together material in the restricted opening. To ease the insertion of the material through the restricted opening, a pull, or draw tape 81, as seen in FIG. 8, can be attached to one side of the bag. The draw tape 81 is pre-threaded through the opening 16, so that it is only necessary to bunch the top walls 25 of the bag together, and then pull on tape 81,

to draw the end through the restricted opening. Tape 81 may be made of the same material as the bag, can be attached to the end of the bag close to opening 16, for example at point 82, or let loose as illustrated in FIG. 8 This pull tab can be made of color-contrasting or different material, as desired. If made of the same material as the bag, it can be cut as the bags are made on an automatic bagging machine, in roll-form, laid across the bag and pushed inwardly, for example by'an air blast or amechanical finger, just prior to or concurrent with forming the seam l5.

The bag construction of the present invention thus provides, as an integral part of the bag itself, a restricted opening through which a portion of the bag material, adjacent the mouth of the bag, can be drawn. Due to the inherent resiliency of the bag material itself which will again flare out after having been tightly bunched to be drawn through the opening, the

- bag will effectively hold contents placed therein, even against upsetting and turning over. The construction shown in FIGS. 1, 2, and 6 is the simplest, least wasteful of bag material; and easiest to produce on existing machinery; the constructions shown in accordance with FIGS. 4, 5, and 7 have the advantages of greater resistance to moisture penetration, or exchange of gasses, and liquids between the inside and the outside of the bag, requiring, however, slightly greater dexterity in closing the bag and a slightly greater amount of material. The material above the seams in FIGS. 4 and 5 is not, however, wasted since when used as a liner, it would normally be folded over the structure which it is designed to protect.

Various changes and modifications, as determined by the use to which the bags are to be put can be made. For example, it would be possible to modify the structure of FIG. 7 by not placing the strap 71 against the-back wall of the bag, but rather by forming as-an attachment, or asan integral part of the bag, a tab which projects from the outline of the bag, with a slit, or other opening therein through which the remainder of the bag can be drawn. Such tabs can be placed not only at the end of the mouth, but also at the side of the bag. Since such a the bag, and a seam line interconnecting adjacent Wall regions of the bag located inwardly from the lateral side of the bag to define said passageway, between the wall regions of the bag and the lateral side thereof.

3. Bag structure according to claim 2, wherein said seam extends essentially parallel to a lateral edge of a wall (FIGS. 2, 3). a

4. Bag structure according to claim 2, wherein said seam is located below the edge of a wall defining the filling opening of the bag (FIG. 2).

5. Bag structure according to claim 2, wherein said seam is a seam line extending from the filling opening end of a wall of I the bag towards the other end of the bag for a limited distance construction requires additional material, however, it is not shown or referred to in further detail.

The seams need not be lines, as shown in the drawings, but may for bags of smaller size and requiring low closure strength, for example for sandwich bags, be merely plasticwelded spots, or loops suitably placed on the bag structure to provide for the restricted opening through which the remainder of the mouth portion of the bag can be drawn. Various other changes and modifications to the bag structure may be made within the inventive concept.

I claim:

l. Bag structure comprising walls of resilient, flexible thermoplastic material having a filling opening to provide access to the inside of the bag between the walls thereof;

means defining a passageway formed in the vicinity of the mouth of the bag, said means being formed in one of the walls of the bag, to provide a passageway just slightly greater than the cross-sectional area of the entire material of the walls in the region of the mouth of the bag, when compressed and gathered tightly together to pennit the free ends of the compressed tightly gathered material of the walls to be drawn from the inside of the bag through the passageway and flare out beyond the passageway to close the bag, the flared ends securing the closure of the bag.

2. Bag structure according to claim 1, wherein said means defining said passageway comprises a portion of the mouth of to define said passageway between the wall of the bag and the edge thereof (FIG. 3). a

6. Bag structure according to claim l, wherein said means defining said passageway comprises a portion of the bag in the vicinity of the mouth thereof, and a slit formed at a lateral edge of the bag located below the ends of the walls defining the filling opening (FIG. 4). v o

,7. Bag structure according to claim 6, including a pair of seams, one each at opposite sides of said slit to provide for reinforcement of the terminal ends of the slit and prevent tearing of said slit when said tightly gathered wall regions from' the mouth of the bags are inserted through the passageway defined by said slit.

8. Bag structure according to claim 7, wherein said seams are seam lines extending essentially parallel, or converging towards said slit.

9. Bag structure according to claim 1, wherein said means defining said passageway comprises a folded-over section of material of the bag adjacent the filling opening thereof;

seam lines extending through said folded-over section;

and a slit formed between said seam lines, said slit defining said passageway (FIG. 5).

10. Bag structure according to claim 9, wherein said foldedover sections are formed by gussets folded in the side walls of the bag (FIG. 5b).

11. Bag structure according to claim 1, wherein said means defining said passageway comprises a cross strap secured to a wall of said bag adjacent the filling opening thereof, said cross strap leaving a free space beneath said strap and the wallto define said passageway.

' 12. Bag structure according to claim 11, wherein said cross strap is of a material different from the material of the wall of the bag to which it is attached.

, 13. Bag structure according to claim 1, further including a pull tape attached to a portion of the wall adjacent the filling opening thereof, said pull tape being pre-threaded through said passageway to provide a guide leader for drawing said walls, when gathered tightly together, through 'said passageway (FIG. 8). I

14. Bag structure according to claim 1, where said bag has a gusset formed in the side wall thereof;

and said means defining said passageway comprises a portion of the filling opening defined by a wall and an adjacent portion of a gusset, and a seam interconnecting said wall and said gusset (FIG. 6).

15. In a bag structure, comprising walls of thermoplastic sheet material, means formed in one wall of the'bag structure defining a restricted passageway adjacent the mouth of said bag, said passageway being slightly larger than the cross-sectional area of the walls when gathered together and compressed and located to permit the free ends of the gathered and compressed material of the walls to be drawn from the inside of the bag through the passageway and flare out therebeyond;

and a seam formed on said wall adjacent said passageway.

16. In the bag of claim 15, said seam interconnecting oppositely located wall portions of said bag, to restrict the free opening of the mouth thereof in a region adjacent the mouth, and form said passageway.

17. Method of closing a bag of resilient, thermoplastic material comprising forming a restricted passageway integral with a wall of the bag and adjacent the mouth of the bag;

tightly gathering together the entire end portion of the material of the bag adjacent said opening;

through said passageway, and permitting said tightly gathered material to be released and flare beyond said passageway.

18. A bag structure according to claim 1 wherein the bag and drawing said tightly gathered material through said wallmaterialisapolyethylene restricted passageway from the inside of the bag, pulling it 

1. Bag structure comprising walls of resilient, flexible thermoplastic material having a filling opening to provide access to the inside of the bag between the walls thereof; means defining a passageway formed in the vicinity of the mouth of the bag, said means being formed in one of the walls of the bag, to provide a passageway just slightly greater than the cross-sectional area of the entire material of the walls in the region of the mouth of the bag, when compressed and gathered tightly together to permit the free ends of the compressed tightly gathered material of the walls to be drawn from the inside of the bag through the passageway and flare out beyond the passageway to close the bag, the flared ends securing the closure of the bag.
 2. Bag structure according to claim 1, wherein said means defining said passageway comprises a portion of the mouth of the bag, and a seam line interconnecting adjacent wall regions of the bag located inwardly from the lateral side of the bag to define said passageway, between the wall regions of the bag and the lateral side thereof.
 3. Bag structure according to claim 2, wherein said seam extends essentially parallel to a lateral edge of a wall (FIGS. 2, 3).
 4. Bag structure according to claim 2, wherein said seam is located below the edge of a wall defining the filling opening of the bag (FIG. 2).
 5. Bag structure according to claim 2, wherein said seam is a seam line extending from the filling opening end of a wall of the bag towards the other end of the bag for a limited distance to define said passageway between the wall of the bag and the edge thereof (FIG. 3).
 6. Bag structure according to claim 1, wherein said means defining said passageway comprises a portion of the bag in the vicinity of the mouth thereof, and a slit formed at a lateral edge of the bag located below the ends of the walls defining the filling opening (FIG. 4).
 7. Bag structure according to claim 6, including a pair of seams, one each at opposite sides of said slit to provide for reinforcement of the terminal ends of the slit and prevent tearing of said slit when said tightly gathered wall regions from the mouth of the bags are inserted through the passageway defined by said slit.
 8. Bag structure according to claim 7, wherein said seams are seam lines extending essenTially parallel, or converging towards said slit.
 9. Bag structure according to claim 1, wherein said means defining said passageway comprises a folded-over section of material of the bag adjacent the filling opening thereof; seam lines extending through said folded-over section; and a slit formed between said seam lines, said slit defining said passageway (FIG. 5).
 10. Bag structure according to claim 9, wherein said folded-over sections are formed by gussets folded in the side walls of the bag (FIG. 5b).
 11. Bag structure according to claim 1, wherein said means defining said passageway comprises a cross strap secured to a wall of said bag adjacent the filling opening thereof, said cross strap leaving a free space beneath said strap and the wall to define said passageway.
 12. Bag structure according to claim 11, wherein said cross strap is of a material different from the material of the wall of the bag to which it is attached.
 13. Bag structure according to claim 1, further including a pull tape attached to a portion of the wall adjacent the filling opening thereof, said pull tape being pre-threaded through said passageway to provide a guide leader for drawing said walls, when gathered tightly together, through said passageway (FIG. 8).
 14. Bag structure according to claim 1, where said bag has a gusset formed in the side wall thereof; and said means defining said passageway comprises a portion of the filling opening defined by a wall and an adjacent portion of a gusset, and a seam interconnecting said wall and said gusset (FIG. 6).
 15. In a bag structure, comprising walls of thermoplastic sheet material, means formed in one wall of the bag structure defining a restricted passageway adjacent the mouth of said bag, said passageway being slightly larger than the cross-sectional area of the walls when gathered together and compressed and located to permit the free ends of the gathered and compressed material of the walls to be drawn from the inside of the bag through the passageway and flare out therebeyond; and a seam formed on said wall adjacent said passageway.
 16. In the bag of claim 15, said seam interconnecting oppositely located wall portions of said bag, to restrict the free opening of the mouth thereof in a region adjacent the mouth, and form said passageway.
 17. Method of closing a bag of resilient, thermoplastic material comprising forming a restricted passageway integral with a wall of the bag and adjacent the mouth of the bag; tightly gathering together the entire end portion of the material of the bag adjacent said opening; and drawing said tightly gathered material through said restricted passageway from the inside of the bag, pulling it through said passageway, and permitting said tightly gathered material to be released and flare beyond said passageway.
 18. A bag structure according to claim 1 wherein the bag wall material is a polyethylene film. 